Analysis of Sparse and Noisy Ocean Current Data Using Flow Decomposition. Part I: Theory

Chu, Peter C.; Ivanov, Leonid M.; Korzhova, Tatiana P.; Margolina, Tetyana; Melnichenko, Oleg

doi:10.1175/1520-0426(2003)20<478:aosano>2.0.co;2

Cited by 44 publications

(60 citation statements)

References 20 publications

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“…To overcome this weakness, a recently developed Optimal Spectral Decomposition method (Chu et al, 2003a(Chu et al, , 2003b(Chu et al, , 2004 was used to reconstruct the OSCAR data at each time instance, which is represented by V(x, y, t), where (x, y) are horizontal coordinates, and t is time.…”

Section: Oscar Data and Reconstructionmentioning

confidence: 99%

Observational studies on association between eastward equatorial jet and Indian Ocean dipole

Chu

2010

J Oceanogr

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Section: Oscar Data and Reconstructionmentioning

confidence: 99%

Observational studies on association between eastward equatorial jet and Indian Ocean dipole

Chu

2010

J Oceanogr

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“…The Vapnik-Chervonenkis dimension (Vapnik 1983;Chu et al 2003aChu et al , 2015 was used to determine the optimal mode truncation K OPT . As depicted in Appendix D, it depends only on the ratio of the total number of observational points (M) versus spectral truncation (K) and does not depend on the total number of model grid (32) points (N).…”

Section: Error Analysismentioning

confidence: 99%

Ocean spectral data assimilation without background error covariance matrix

2016

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Predetermination of background error covariance matrix B is challenging in existing ocean data assimilation schemes such as the optimal interpolation (OI). An optimal spectral decomposition (OSD) has been developed to overcome such difficulty without using the B matrix. The basis functions are eigenvectors of the horizontal Laplacian operator, pre-calculated on the base of ocean topography, and independent on any observational data and background fields. Minimization of analysis error variance is achieved by optimal selection of the spectral coefficients. Optimal mode truncation is dependent on the observational data and observational error variance and determined using the steep-descending method. Analytical 2D fields of large and small mesoscale eddies with white Gaussian noises inside a domain with four rigid and curved boundaries are used to demonstrate the capability of the OSD method. The overall error reduction using the OSD is evident in comparison to the OI scheme. Synoptic monthly gridded world ocean temperature, salinity, and absolute geostrophic velocity datasets produced with the OSD method and quality controlled by the NOAA National Centers for Environmental Information (NCEI) are also presented.

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“…Conditions 4-6 corresponded to near-resonance nonlinear interactions described by the Poisson bracket {η, η} for quasi-geostrophic flows or { , η} without the geostrophic approximation ( is "a stream" function) (Pedlosky, 1987). The "stream" function can be defined through a two-scalar potential representation of a three-dimensional incompressible flow; see, for example, Moffatt (1978) or Chu et al (2003) for applications. Obviously, in this case, the two scalar potentials and defined here are not the same as the stream function and velocity potential of a two-dimensional flow (this is discussed in Chu et al, 2003).…”

Section: Wavelet Analysismentioning

confidence: 99%

“…The "stream" function can be defined through a two-scalar potential representation of a three-dimensional incompressible flow; see, for example, Moffatt (1978) or Chu et al (2003) for applications. Obviously, in this case, the two scalar potentials and defined here are not the same as the stream function and velocity potential of a two-dimensional flow (this is discussed in Chu et al, 2003). The statistical stability needed for detection of triads and quartets was achieved through special smoothing with a priori constraints applied (Ivanov et al, 2012a).…”

Section: Wavelet Analysismentioning

confidence: 99%

On quartet interactions in the California Current system

Ivanov

Collins

Margolina

2014

Nonlin. Processes Geophys.

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Abstract. Sea surface height (SSH) altimetry observations for 1992 to 2009 off California are used to show that observed quasi-zonal jets were likely driven by near-resonance interactions between different scales of the flow. Quartet (modulational) instability dominated and caused non-local transfer of energy from waves and eddies to biannual oscillations and quasi-zonal jets. Two types of quartets were identified: those composed of scales corresponding to (a) quasi-zonal jets, annual and semiannual Rossby waves and mesoscale eddies, and (b) biannual oscillations, semiannual Rossby waves and mesoscale eddies. The spectral centroid regularly shifted into the domain of low-order modes. However, the spectrum of SSHs does not demonstrate a power behavior. This says that the classical inverse cascade is absent. For a case with bottom friction, quartet instability required the existence of a certain level of dissipativity in the flow.

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Analysis of Sparse and Noisy Ocean Current Data Using Flow Decomposition. Part I: Theory

Cited by 44 publications

References 20 publications

Observational studies on association between eastward equatorial jet and Indian Ocean dipole

Observational studies on association between eastward equatorial jet and Indian Ocean dipole

Ocean spectral data assimilation without background error covariance matrix

On quartet interactions in the California Current system

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